This invention particularly relates to binding straps having fastening means by which the strap may be wrapped around an article or articles and fastened in place; the invention also pertains to the general field of recallable self-mating fasteners.
Reclosable fastener products have long been sought as replacement candidates for common bundling products such as cable ties. Some examples of prior efforts are illustrated in U.S. Pat. Nos. 1,164,697; 3,586,220; 4,169,303; 4,215,687; 4,684,559; 4,706,914; 4,963,410; and 5,177,986. But most of the suggested products include fastening structures that are bulky and two-part in nature, such as hook-and-loop fasteners or male-female fastener pairs, which tend to be too expensive for many applications and to have other significant disadvantages. Other suggested products have inadequate peel strength or other properties that are desired for a bundling use.
The present invention provides a new method for binding an article or group of articles, and further provides a new binding strap for carrying out such a binding operation. The new method generally comprises at least partially surrounding at least one article with a first elongate strap portion that comprises a base sheet configured on at least one surface with an array of parallel, narrowly spaced, elastically deformable ribs that project integrally from the base sheet. The array of ribs establishes a first self-mating fastening surface, i.e., the fastening surface can be pressed against and thereby interconnected with an identical fastening surface. The ribs comprise a stem portion attached to and substantially upright from the base sheet and a flange attached to at least one side of the stem portion and spaced from the base sheet. The outer portion of the underside surface of at least some flanges projects toward the base sheet; and at least some flanges have a substantial thickness over most of their width such that the stem portion deforms in preference to the flange during peel-type disengagement from an identical fastening surface. To bind the article, the first fastening surface is interconnected with a second fastening surface carried on a further structural member, which may take various forms, including, for example, a second strap portion, or a separate structural member such as a flat panel provided with a fastening surface.
Some methods of the invention use a single binding strap, as when the further structural member is a second strap portion integrally connected to the first strap portion; and the second fastening surface is typically identical to (i.e., self-mating with) the first fastening surface. The strap may include one or more openings through which one or both ends of the strap may be inserted to complete a binding operation. The first and second fastening surfaces may be disposed on the same major side of a single strap, or they may be disposed on opposite sides of the strap. Some methods use a double-sided binding strap, i.e., a binding strap having a fastening surface on each side of the strap.
When the further structural member used in a method of the invention is a panel or other member separate from the binding strap, the panel may have an opening, and the second fastening surface is carried on the panel adjacent to the opening. Binding can be accomplished by inserting the ends of the first elongate strap portion through the opening and interconnecting the first and second fastening surfaces.
A new binding strap of the invention, useful in a method as described, generally comprises an elongate base sheet having a multiplicity of parallel, narrowly spaced, elastically deformable ribs projecting integrally from the base sheet; the ribs comprising a stem portion attached to and substantially upright from the base sheet and a flange attached to at least one side of the stem portion and spaced from the base sheet; and the array of ribs establishing a first fastening surface that is self-mating. The flanges have a substantial thickness over most of their width such that the stem portions deform in preference to the flanges during peel-type disengagement from an identical fastening surface. Preferably a flange is attached on each side of the stem portion, and at least the outer portions of the underside surface of the flanges project downwardly toward the base sheet to further enhance the strong interconnection achieved by straps of the invention. The strap has a length and width that adapts the strap to be wrapped around one or more articles to apply a binding action on the article(s). Often the binding strap is in tension during such a binding action.
The easiest interengagement of fastening surfaces is obtained when the cross-sectional profile of the array of ribs is substantially uniform over the length of the ribs, but in the direction transverse to the ribs has a regularly repeated deviation from the profile that would be formed by a full population of equally spaced, identical, undivided, symmetric ribs. Preferably such a deviation in profile is provided by using ribs that vary in height one-by-one across the width of the profile.
An important advantage of a new binding strap of the invention is that it can be made by profile extrusion, which establishes an ability to prepare binding straps that meet the cost constraints often present in binding uses. The binding strap can be cut from an extruded polymeric web, with the length of the strap preferably transverse to the machine direction of extrusion, so the ribs are transverse to the length of the strap; straps in which the ribs extend parallel to the length of the strap are also useful and are advantageous for some purposes.